Investigation into mean residence time and filling factor in flighted rotary torrefier
Bibliographic record
Abstract
Torrefaction can upgrade the properties of biomass, making it similar to coal. This study develops an innovative indirectly heated two‐stage rotating drum‐type torrefier where biomass moves due to the rotation of inclined cylindrical reactors. The rotary reactors consist of three rectangular flights placed axially along the reactor. This paper mainly investigates the mean residence time and filling factor of reactors operated at steady and plug flow conditions. Semi‐empirical expressions using dimensionless correction constants for the mean residence time and the filling factor were proposed. Experiments keeping a constant solid flow rate at the dryer inlet were conducted in order to measure filling factor and mean residence time at different angular speeds and inclinations of reactors (dryer and torrefier). Mean residence times of 5.8 min at 8 rpm and 3°, and of 27.5 min at 4 rpm and 1° were found in the dryer (diameter: 64 mm, length: 610 mm), whereas they were 4.7 and 21.4 min in the torrefier (diameter: 100 mm, length: 762 mm) at respective operating conditions. Filling factors of 3.0 % at 8 rpm and 3°, and 14.3 % at 4 rpm and 1° were found in the dryer, whereas they were 0.8 % and 3.6 % in the torrefier at the corresponding angular speed and inclination. Measured and predicted mean residence times were also compared and validated against those of other investigators. The proposed expressions, which include the effects of different operating and geometrical parameters, have strong predictive power and may be useful in scaling‐up a rotary torrefier.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".